In a projection type image display device (a projector) which projects an image onto a screen or the like, an image formed by a display element of a liquid crystal panel or the like is projected onto a screen or the like while being enlarged by a projection lens. For that reason, when the projection lens is vibrated, the shaking of the image projected onto the screen is displayed in an enlarged state. Thus, a problem arises in that an image quality is deteriorated and the image is visually undesirable.
As a technique of preventing the shaking of the projection image, Patent Document 1 discloses a configuration in which a focusing lens portion and a rack portion are mechanically separated from each other and an elastic member is interposed in a separation portion in order to prevent the shaking of an image on a screen caused by a vibration of a lens device due to an impact generated when a focusing motor starts to rotate.